1. Field of the Invention
The present invention relates to an illuminating device capable of efficiently controlling light emitted from a light source, and to a photographing apparatus having the same.
2. Description of Related Art
A known type of illuminating device for projecting light from a light source onto a subject via an optical path in which the light is reflected a plurality of times is disclosed in, for example, Japanese Laid-Open Patent Application No. Hei 4-16833. This illuminating device is intended to obtain diffused light for a subject lying at a short distance, and is arranged to diffuse light rays emitted from a light source by reflecting the light rays a plurality of times by means of a plurality of plane mirrors disposed approximately in parallel at the front of the light source, and to project the diffused light rays onto the subject lying at the short distance.
Another known type of illuminating device is proposed in Japanese Laid-Open Patent Application No. Sho 59-165037. In this illuminating device, light rays emitted from a flash emission tube are gathered to form a flat beam at a light gathering part adjacent to which bundled optical fibers are appropriately disposed so that a predetermined light intensity distribution can be obtained.
However, the former conventional example has the problem that since the plane mirrors disposed approximately in parallel and having a diffusion effect are used as a light guide path, light losses are liable to occur during reflection at the mirror surfaces. This conventional example, because of its light intensity reducing capability, is convenient for photography during which a subject at a short distance needs to be illuminated, such as close-up photography, but has the disadvantage of being unsuited to the purpose of efficiently gathering light to illuminate a subject lying at a long distance.
In the latter conventional example, the light entrance portions of the optical fibers are disposed at a position where the light rays from the flash emission tube are to be focused by a reflector, so that the light rays can be guided to the light exit portions of the optical fibers. However, this conventional example has the problem that since the optical fibers cannot be closely laid because of their cylindrical shapes, the loss of an amount of light occurs. In addition, there are other problems, such as the optical fibers being extremely expensive and light distribution characteristics being impossible to control within the optical fibers (the state of light gathering being impossible to vary between a light entrance side and a light exit side).